Responses to N deficiency in stay green and non-stay green Argentinean hybrids of maize

ANTONIETTA MARIANA; GUIAMET JUAN J.; TAMBUSSI EDUARDO; ACCIARESI HORACIO

JOURNAL OF AGRONOMY AND CROP SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Año: 2016 vol. 202 p. 231 - 242

0931-2250

Breeding has developed better yielding maize hybrids for low N environments with delayed leaf senescence (DLS). Here, we studied if DLS among modern hybrids can further improve yield under N-limiting conditions. In two field experiments, four maize hybrids with different senescence behavior were grown under three N levels, from 0 to 200 kg N ha-1 (N0, N100 and N200). The effects of N deficiency on leaf senescence varied depending on canopy layer and genotype: in comparison with the non-stay green (SG) reference DK682, the moderately SG AX878 only delayed senescence at the mid and upper canopy layers while the strongly SG NK880 delayed senescence of all layers. At N0, yield was reduced by 20-36%; genotypic variation for yield was related to kernel number per plant (r2=0.86) and higher yields were achieved by the SGs NK880 and AX878. In contrast, at N100 and N200 yield related mainly to average kernel weight (r2=0.84 and r2=0.70 respectively). Delayed leaf senescence in the SGs was linked to lower kernel N concentrations. Across N levels, kernel weight positively related to kernel N concentration, with a steeper slope (P